A liquid developer for electrostatic charge images is generally composed of a dispersion of coloring agent particles such as carbon black, phthalocyanine, etc., in a high insulating low dielectric constant carrier liquid such as an aliphatic hydrocarbon, toluene, a halogenated hydrocarbon, etc. Recently, coloring agent particles having stuck to the surfaces thereof a resin for imparting thereto a charge controlling property, a dispersibility, a fixability, etc., are frequently used as toners for the liquid developer. Also, additives such as a dispersing agent, a polarity controlling agent, etc., are, if necessary, added to the carrier liquid.
As the resins which are ordinarily used for such coloring agents, there are various natural resins and synthetic resins such as resin, natural rubber, an alkyd resin, a phenol resin, an epoxy resin, a pentaerythritol resin, an acryl resin, synthetic rubber, etc. However, the use of these resins has the following problems for practical use. That is, in the case of using a natural resin, it is difficult to obtain products having a constant quality and also in the case of using synthetic resins such as an acryl resin, etc., sufficient dispersibility and fixability are not always obtained and also the coloring agent particles are liable to cause aggregation or sedimentation with the passage of time.